From b7e393dffb2df78691628ab0cc936240c6195186 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alejandro=20Fern=C3=A1ndez?=
 <alejandro.fernandez@elastic.co>
Date: Wed, 27 May 2020 16:08:41 +0200
Subject: [PATCH] [Logs UI] Avoid a crash when a highlight term doesn't exist
 (#67332)

---
 .../common/http_api/log_entries/highlights.ts | 17 +++++++----
 .../server/routes/log_entries/highlights.ts   | 20 +++++++++----
 .../apis/infra/log_entry_highlights.ts        | 28 +++++++++++++++++++
 3 files changed, 55 insertions(+), 10 deletions(-)

diff --git a/x-pack/plugins/infra/common/http_api/log_entries/highlights.ts b/x-pack/plugins/infra/common/http_api/log_entries/highlights.ts
index f6d61a7177b4..811cf85db888 100644
--- a/x-pack/plugins/infra/common/http_api/log_entries/highlights.ts
+++ b/x-pack/plugins/infra/common/http_api/log_entries/highlights.ts
@@ -51,11 +51,18 @@ export type LogEntriesHighlightsRequest = rt.TypeOf<typeof logEntriesHighlightsR
 
 export const logEntriesHighlightsResponseRT = rt.type({
   data: rt.array(
-    rt.type({
-      topCursor: logEntriesCursorRT,
-      bottomCursor: logEntriesCursorRT,
-      entries: rt.array(logEntryRT),
-    })
+    rt.union([
+      rt.type({
+        topCursor: rt.null,
+        bottomCursor: rt.null,
+        entries: rt.array(logEntryRT),
+      }),
+      rt.type({
+        topCursor: logEntriesCursorRT,
+        bottomCursor: logEntriesCursorRT,
+        entries: rt.array(logEntryRT),
+      }),
+    ])
   ),
 });
 
diff --git a/x-pack/plugins/infra/server/routes/log_entries/highlights.ts b/x-pack/plugins/infra/server/routes/log_entries/highlights.ts
index c95032f56987..be6be88e4b5e 100644
--- a/x-pack/plugins/infra/server/routes/log_entries/highlights.ts
+++ b/x-pack/plugins/infra/server/routes/log_entries/highlights.ts
@@ -79,11 +79,21 @@ export const initLogEntriesHighlightsRoute = ({ framework, logEntries }: InfraBa
 
         return response.ok({
           body: logEntriesHighlightsResponseRT.encode({
-            data: entriesPerHighlightTerm.map((entries) => ({
-              entries,
-              topCursor: entries[0].cursor,
-              bottomCursor: entries[entries.length - 1].cursor,
-            })),
+            data: entriesPerHighlightTerm.map((entries) => {
+              if (entries.length > 0) {
+                return {
+                  entries,
+                  topCursor: entries[0].cursor,
+                  bottomCursor: entries[entries.length - 1].cursor,
+                };
+              } else {
+                return {
+                  entries,
+                  topCursor: null,
+                  bottomCursor: null,
+                };
+              }
+            }),
           }),
         });
       } catch (error) {
diff --git a/x-pack/test/api_integration/apis/infra/log_entry_highlights.ts b/x-pack/test/api_integration/apis/infra/log_entry_highlights.ts
index e704a8a938dc..823c8159a136 100644
--- a/x-pack/test/api_integration/apis/infra/log_entry_highlights.ts
+++ b/x-pack/test/api_integration/apis/infra/log_entry_highlights.ts
@@ -46,6 +46,34 @@ export default function ({ getService }: FtrProviderContext) {
         before(() => esArchiver.load('empty_kibana'));
         after(() => esArchiver.unload('empty_kibana'));
 
+        it('Handles empty responses', async () => {
+          const { body } = await supertest
+            .post(LOG_ENTRIES_HIGHLIGHTS_PATH)
+            .set(COMMON_HEADERS)
+            .send(
+              logEntriesHighlightsRequestRT.encode({
+                sourceId: 'default',
+                startTimestamp: KEY_BEFORE_START.time,
+                endTimestamp: KEY_AFTER_END.time,
+                highlightTerms: ['some string that does not exist'],
+              })
+            )
+            .expect(200);
+
+          const logEntriesHighlightsResponse = pipe(
+            logEntriesHighlightsResponseRT.decode(body),
+            fold(throwErrors(createPlainError), identity)
+          );
+
+          expect(logEntriesHighlightsResponse.data).to.have.length(1);
+
+          const data = logEntriesHighlightsResponse.data[0];
+
+          expect(data.entries).to.have.length(0);
+          expect(data.topCursor).to.be(null);
+          expect(data.bottomCursor).to.be(null);
+        });
+
         it('highlights built-in message column', async () => {
           const { body } = await supertest
             .post(LOG_ENTRIES_HIGHLIGHTS_PATH)